Database systems typically employ homogenous configurations of hardware, such that the system data is stored on an array of devices having identical characteristics. For example, all data may be stored on devices having the same storage capacities and data transfer speeds. Often, such a system is adequate when all of the data within an organization can be considered to be of the same importance or value.
In many organizations, however, certain data is considered to be of greater importance than other data. For example, some data may be associated with higher application performance requirements, enhanced security requirements, or otherwise require greater robustness or lower device failure rates. A conventional database system will store data on storage devices without regard for these requirements. As a result, valuable data may be stored on devices that are not qualified to store that data and hence, important data may be subject to unacceptable security risks and risks of loss due to device failure. Alternatively, all data is stored with all possible precautions, i.e., using the highest levels of encryption and only the most reliable devices. This approach, however, is extremely inefficient, as it requires the storage of relatively unimportant data on highly expensive systems.